<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="changeAllHandler" />
    </label>
    <span>
      <span>已完成{{ hasChecked }}</span> / 全部{{ todoList.length }}
    </span>
    <button class="btn btn-danger" @click="deleteAllCheckedHandle">
      清除已完成任务
    </button>
  </div>
</template>

<script>
import PubSub from "pubsub-js";
export default {
  name: "Footer",
  data() {
    return {
      todoList: [],
    };
  },
  watch: {
    todoList: {
      deep: true,
      immediate: true,
      handler() {
        PubSub.subscribe("todoList", (_, value) => {
          this.todoList = value;
        });
      },
    },
  },
  computed: {
    hasChecked() {
      const result = this.todoList.filter((item) => item.done === true);
      return result.length;
    },

    changeAllHandler: {
      get() {
        return (
          this.hasChecked === this.todoList.length && this.todoList.length !== 0
        );
      },
      set(value) {
        this.$bus.$emit("updateAllChecked", value);
      },
    },
  },

  methods: {
    deleteAllCheckedHandle() {
      this.$bus.$emit("deleteAllChecked");
    },
  },
};
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>